Re: [PATCH v2] infiniband: remove WARN that is not kernel bug

Leon Romanovsky
2016-11-21T11:44:26Z

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On Mon, Nov 21, 2016 at 11:30:21AM +0100, Dmitry Vyukov wrote:
> On Mon, Nov 21, 2016 at 11:25 AM, Miroslav Benes <mbenes@suse.cz> wrote:
> > On Mon, 21 Nov 2016, Dmitry Vyukov wrote:
> >
> >> WARNINGs mean kernel bugs.
> >> The one in ucma_write() points to user programming error
> >> or a malicious attempt. This is not a kernel bug, remove it.
> >>
> >> BUG/WARNs that are not kernel bugs hinder automated testing effots.
> >>
> >> Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
> >> Cc: Doug Ledford <dledford@redhat.com>
> >> Cc: Sean Hefty <sean.hefty@intel.com>
> >> Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
> >> Cc: Leon Romanovsky <leon@kernel.org>
> >> Cc: linux-rdma@vger.kernel.org
> >> Cc: linux-kernel@vger.kernel.org
> >> Cc: syzkaller@googlegroups.com
> >>
> >> ---
> >> Changes since v1:
> >> - added printk_once
> >> ---
> >> drivers/infiniband/core/ucma.c | 5 ++++-
> >> 1 file changed, 4 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
> >> index 9520154..405d0ce 100644
> >> --- a/drivers/infiniband/core/ucma.c
> >> +++ b/drivers/infiniband/core/ucma.c
> >> @@ -1584,8 +1584,11 @@ static ssize_t ucma_write(struct file *filp, const char __user *buf,
> >> struct rdma_ucm_cmd_hdr hdr;
> >> ssize_t ret;
> >>
> >> - if (WARN_ON_ONCE(!ib_safe_file_access(filp)))
> >> + if (!ib_safe_file_access(filp)) {
> >> + printk_once("ucma_write: process %d (%s) tried to do something hinky\n",
> >> + task_tgid_vnr(current), current->comm);
> >> return -EACCES;
> >> + }
> >>
> >> if (len < sizeof(hdr))
> >> return -EINVAL;
> >
> > FWIW, WARN_ON_ONCE came with commit e6bd18f57aad ("IB/security: Restrict
> > use of the write() interface"). Would it make sense to change the other
> > places as well?
>
>
> I guess so.
> Can I ask somebody of infiniband maintainers to take care of this?

Please see below,
Hope it helps.

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From e0bfe4771591f9ffbcaa4e66d6257ed95e2d7188 Mon Sep 17 00:00:00 2001
From: Leon Romanovsky <leonro@mellanox.com>
Date: Mon, 21 Nov 2016 13:30:59 +0200
Subject: [PATCH] IB/{core, qib}: Remove WARN that is not kernel bug

WARNINGs mean kernel bugs, in this case, they are placed
to mark programming errors and/or malicious attempts.

BUG/WARNs that are not kernel bugs hinder automated testing efforts.

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
---
drivers/infiniband/core/ucm.c | 5 ++++-
drivers/infiniband/core/ucma.c | 5 ++++-
drivers/infiniband/core/uverbs_main.c | 5 ++++-
drivers/infiniband/hw/qib/qib_file_ops.c | 5 ++++-
4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/core/ucm.c b/drivers/infiniband/core/ucm.c
index 7713ef0..0076b55 100644
--- a/drivers/infiniband/core/ucm.c
+++ b/drivers/infiniband/core/ucm.c
@@ -1104,8 +1104,11 @@ static ssize_t ib_ucm_write(struct file *filp, const char __user *buf,
struct ib_ucm_cmd_hdr hdr;
ssize_t result;

- if (WARN_ON_ONCE(!ib_safe_file_access(filp)))
+ if (!ib_safe_file_access(filp)) {
+ pr_err_once("ucm_write: process %d (%s) tried to do something hinky\n",
+ task_tgid_vnr(current), current->comm);
return -EACCES;
+ }

if (len < sizeof(hdr))
return -EINVAL;
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 9520154..31fa27f 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1584,8 +1584,11 @@ static ssize_t ucma_write(struct file *filp, const char __user *buf,
struct rdma_ucm_cmd_hdr hdr;
ssize_t ret;

- if (WARN_ON_ONCE(!ib_safe_file_access(filp)))
+ if (!ib_safe_file_access(filp)) {
+ pr_err_once("ucma_write: process %d (%s) tried to do something hinky\n",
+ task_tgid_vnr(current), current->comm);
return -EACCES;
+ }

if (len < sizeof(hdr))
return -EINVAL;
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 44b1104..329eb15 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -746,8 +746,11 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
int srcu_key;
ssize_t ret;

- if (WARN_ON_ONCE(!ib_safe_file_access(filp)))
+ if (!ib_safe_file_access(filp)) {
+ pr_err_once("uverbs_write: process %d (%s) tried to do something hinky\n",
+ task_tgid_vnr(current), current->comm);
return -EACCES;
+ }

if (count < sizeof hdr)
return -EINVAL;
diff --git a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c
index 382466a..b43ea52 100644
--- a/drivers/infiniband/hw/qib/qib_file_ops.c
+++ b/drivers/infiniband/hw/qib/qib_file_ops.c
@@ -2066,8 +2066,11 @@ static ssize_t qib_write(struct file *fp, const char __user *data,
ssize_t ret = 0;
void *dest;

- if (WARN_ON_ONCE(!ib_safe_file_access(fp)))
+ if (!ib_safe_file_access(fp)) {
+ pr_err_once("qib_write: process %d (%s) tried to do something hinky\n",
+ task_tgid_vnr(current), current->comm);
return -EACCES;
+ }

if (count < sizeof(cmd.type)) {
ret = -EINVAL;
--
2.7.4

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